Jack McClelland was a Canadian publisher and president of the publishing house McClelland & Stewart (M&S). M&S had begun as a partnership between McClelland's father, John McClelland, and Frederick Goodchild, with the majority of its publishing being devoted to Protestant literature. Jack began working at M&S in 1946, and by 1961 he was president of the company. Under his leadership M&S changed its focus from religious works to the publishing of Canadian literature.

Jack McClelland saw M&S as a medium through which Canadian literature could be made more accessible to the public, and thus promote Canadian nationalism through culture. Many of the most prominent Canadian authors such as novelists Margaret Atwood and Mordicai Richeler, environmentalist Farley Mowat, and historians such as Pierre Burton and Conrad Black had their works published through M&S. In addition, the company was the primary publisher of English translations of Quebecois literature, such as novels by Michel Trembley and Claude Aubry, as well as the various political literature of the Quiet Revolution by those such as Rene Levesque and Pierre Vallieres.

Jack McClelland, like many contemporary Canadians, was concerned with the rising levels of foreign control in the Canadian economy, and the feeling that Canada would not last into the next millennium if things stayed the way they were. This led McClelland towards Canadian nationalism as promoted by the Committee for an Independent Canada (CIC). This group focused on gaining Canada a greater degree of economic freedom, particularly in areas deemed vital to Canada’s economy and culture. This focus by McClelland on ensuring the independence of the Canadian economy would eventually lead to him joining the CIC as a co-chairmen with Claude Ryan.

McClelland and Stewart Inc., under the guidance of Jack McClelland, would reshape Canadian publishing into something that is still felt today by many Canadian authors. When Jack McClelland became sole owner in 1968, he transitioned the company to only publishing Canadian authors. This was a huge gamble, but due to the cultural revival in Canada, which saw many universities being opened and needing new books, the gamble paid off . This new focus would also see McClelland and Stewart strive to make sure all Canadian authors received their recognition and protection in Canadian society and the rest of the world. In the end Jack McClelland's goal was a success, as even today many Canadian authors are known around the world as great writers due to the actions of McClelland and Stewart Inc.